
are HÃ¶lder continuous goes back to the classical work of E. De Giorgi in [1]} using Caccioppoli inequalities and J. Nash in [2]} using parabolic equations. Later the same result was also proved using Harnack inequalities by J. Moser in [3]}. Here of course as usual this result holds true under the uniform ellipticity assumption
\(\lambda \vert v\vert ^2\le \langle A(x)v,v\rangle \le \Lambda \vert v\vert ^2\) 
